The mineralization of calcium phosphates will be studied under highly reproducible conditions by the addition of well-characterized seed material to stable supersaturated solutions of calcium phosphate both at physiological pH and at pH levels typical of those leading to the formation of carious lesions. A new technique of constant composition will be exploited over a wide range of supersaturation and ionic strength. The stoichiometry of the phases formed at various times will be determined. Solid phases will also be characterized by x-ray diffraction, specific surface area measurements, and scanning electron microscopy. Both synthetic calcium phosphates and mineral components of teeth will be studied. The influence of anti-caries and anti-calculus agents upon the rate and course of the mineralization processes will be studied. Experiments will also be made with fluoroapatite in order to yield information about the mechanism of topical fluoride treatments.